The immune system is responsible for protecting us from disease, but sometimes it fails to work properly, and this can lead to disability. Aquired immune deficiency syndrome is caused when an HIV infection damages immune cells and suppresses the immune system. On the other end of the sprectrum, abnormal immune activity that causes inflammation or the build up of antibodies is responsible for autoimmune diseases like Type I diabetes, Grave's disease, multiple sclerosis, Addison's disease, myasthenia gravis, Hashimoto's disease, celiac disease, and even psoriasis, as well as connective tissue disorders such as rheumatoid arthritis, lupus, scleroderma, and polymyositis. Social Security treats disorders of the immune system seriously, and has disability listings that lay out the criteria for qualifying for disability for most of these diseases. For the other immune-system-related medical conditions, Social Security looks at how the symptoms of the disease are limiting your abilities and activities.